New Jersey Institute of Technology

Cf Technologies, Inc.

Ken K Chin

Harry Roman

Guanhua Feng

Alan E Delahoy

Ivan Padron

Zimeng Cheng

Haijiang Ou

The present disclosure provides improved thin film photovoltaic devices and related methods of fabrication. More particularly, the present disclosure provides improved CdTe photovoltaic devices and related fabrication methods. Disclosed is a novel thin film photovoltaic device and means for its fabrication. An exemplary device includes a metal oxide layer between the absorber layer and the rear electrode, resulting in an ohmic back contact and having improved device stability. The metal oxide layer can include at least one of silver oxide or copper oxide, and may additionally contain nickel oxide, molybdenum oxide, and/or vanadium oxide. The present disclosure is directed towards formation of a ohmic back contact for solar cells, the back contact having improved stability. In certain embodiments, the present disclosure provides for an ohmic contact to p-type II-VI semiconductors, and to the fabrication of solar cells having improved stability, and to solar panels incorporating such back contact schemes.

System and method for thin film photovoltaic modules and back contact for thin solar cells

Exemplary embodiments of the present disclosure are directed to improve p-type doping (p-doping) of cadmium telluride (CdTe) for CdTe-based solar cells, such as cadmium Sulfide (Cds)/CdTe solar cells. Embodiments can achieve improved p-doping of CdTe by creating a high density of cadmium (Cd) vacancies (V) and subsequently substituting a high density of substitutional defects and/or defect complexes for the Cd vacancies that were created. Formation of a high density of substitutional defects and defect complexes as a p-dopant can improve light-to-electricity conversion efficiency, doping levels or hole concentrations, junction band bending, and/or ohmic contact associated with p-type CdTe (p-CdTe) based solar cells.

p-Doping of CdTe polycrystalline thin film based on Cd vacancy theory

The present invention is a diaphragm-fiber optic sensor (DFOS), interferometric sensor. This DFOS is based on the principles of Fabry-Perot and Michelson/Mach-Zehnder. The sensor is low cost and is designed with high efficiency, reliability, and Q-point stability, fabricated using MEMS (micro mechanic-electrical system) technology, and has demonstrated excellent performance. A DFOS according to the invention includes a cavity between two surfaces: a diaphragm made of silicon or other material with a rigid body (or boss) at the center and clamped along its edge, and the endface of a single mode optic fiber. By utilizing MEMS technology, the gap width between the diaphragm and the fiber endface is made accurately, ranging from 1 micron to 10 microns. To stabilize the Q-point of the DFOS when in use as an acoustic sensor, a system of microchannels is built in the structure of the diaphragm so that the pressure difference on two sides of the diaphragm is kept a constant, independent of the hydraulic pressure and/or low frequency noise when the device is inserted in liquid mediums.

Aligned embossed diaphragm based fiber optic sensor

The theory, design, fabrication, and characterization of MEMS (micro electrical mechanical system) Fabry-Perot diaphragm-fiber optic microphone are described in the present invention. By using MEMS technology in processing and packaging, a square 1.9 mm&#xd7;1.9 mm, 2 &#x3bc; thick SiOdiaphragm with a 350 &#x3bc; square embossed center of silicon is mechanically clamped to the ferrule of a single mode fiber to keep its closeness (5 &#x3bc;) and perpendicular orientation with respect to the diaphragm. Static measurement of optical output power versus the pressure on membrane reveals more than one period of Fabry-Perot interference, thereby generating a Fabry-Perot diaphragm-fiber interferometer device accurately reproducing audible acoustic wave.

MEMS fiber optic microphone

In the present invention of Correlated Modulation Imaging (CMI), the weak optical image signal (and therefore the signal current) is modulated, and the signal integration direction is correlated to the modulation. Therefore, the dark and/or background current, which are not modulated, are cancelled, while the signal current is integrated. As a result, the total integration time of the signal of each pixel is increased, and its signal to noise ratio and dynamic range are improved. Besides, the CMI noise spectrum peaks at the modulation frequency, and therefore, the detector's 1/f and other low frequency noises can be suppressed. In the present invention, the method and theory of CMI, as well as the means and steps for the realization of CMI, are explicitly developed. Two versions of CMOS devices (CMI unit pre-amplifier version 1 and 3), with their circuitry design and testing data are presented as the critical component for correlated modulation imaging. A prototype chip of the CMI circuitries has been fabricated by the MOSIS 0.5-micron foundry. SPICE circuitry simulation has demonstrated the functioning of CMI unit pre-amplifier version 1 and 3 as designed. Experimental work has demonstrated the functioning of CMI unit pre-amplifier version 1 as designed, as well as the key features of CMI&mdash;increase of integration time, and improvement of signal to noise ratio and dynamic range.

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Pine Brook, NJ, United States of America

Ken K Chin